During a sale on the POS, you can assign the order to a customer by simply clicking on Assign customer at the top of the Order summary.
A pop-up will open from which you can
Select an existing customer.
Create a new customer.
Edit existing customer information.
Note that you can assign the customer at the beginning of the order or once the order is completed.
💡 Auto-assignment via membership
When you apply a membership to an order that has no customer yet, the customer linked to the membership is automatically assigned to the order. No need to click Assign customer first. If a customer is already assigned, applying a membership won't override it.